© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Post-transplant lymphoproliferative disorder (PTLD) is an infrequent complication of allogeneic stem cell transplant (allo-SCT). Aims: To estimate the frequency and management of PTLD in Spain and to identify prognostic factors influencing outcomes. Methods: Multicenter, retrospective analysis of allo-SCT performed in 14 transplant units over a 15-year period. Results: 102 PTLD were diagnosed among 12 641 allo-SCT, leading to an estimated frequency of 0.8%. PTLD was diagnosed at a median of 106 days after SCT. Eighty-seven cases (85%) were diagnosed between 2007 and 2013. At diagnosis, 22% and 17% of the patients had gastrointestinal tract and CNS involvement. Eighty-seven (85%) received rituximab treatment, alone or in combination with immunosuppression reduction, with an ORR of 50.6%. With a median follow-up for survivors of 58 months, the 2-year overall survival (OS) was 33% and the PTLD-related mortality 45%. Age ≥ 40 years, malignant underlying disease, non-response to rituximab, and severe thrombocytopenia or lymphocytopenia at PTLD diagnosis were associated with worse overall survival. Conclusions: Only a small proportion of allografted patients were diagnosed a PTLD. Its clinical course was highly aggressive, and prognosis poor, especially in those failing rituximab. The prognostic impact found of the platelet, and lymphocyte count at diagnosis requires further confirmation.